A variety of pumps are in use for removing oil and other liquids from wells. The type of pump selected for use on a particular well is dictated by a number of factors, including the liquid to be pumped.
Submerged mechanical displacement pumps, operated from the surface by reciprocating sucker rods, are conventionally employed to elevate oil to the well surface. Such prior pumping systems, however, are often undesirable to the extent that they entail substantial movement of metal parts which corrode and abrade. Previously developed mechanical pumps produce a relatively limited volume of oil during each pumping cycle, and require relatively large amounts of power in operation. The close tolerances required in manufacturing the parts of such pumps also make the pumps relatively expensive to produce and maintain.
Mechanical displacement pumps normally require a large apparatus located above the ground. A sucker rod and associated machinery must be placed above the well, constituting an eyesore. In certain circumstances, mechanical displacement pumps cannot be used at all because local zoning laws prohibit placement of the large apparatus necessary for operation.
Since mechanical displacement pumps have a large number of moving parts, they are susceptible to breakdowns. These breakdowns are expensive and timeconsuming, resulting in large amounts of down time for the pump. In an oil well, such down time is costly because the well produces no revenues, yet incurs large expenses in the repair operation.
A need has thus arisen for a pump for use with oil wells which is not subject to the disadvantages noted above, but which provides improved pumping operation with reduced energy requirements.